(define true-value t) ;; define boolean value 
(define false-value nil)
true-value
false-value
(if true-value "True" "False")
(if false-value "True" "False")

(define greeting "Hello, World!") ;; define string value 
(define name "Alice")
(define message (+ greeting " My name is " name))
message

(define add (lambda (x y) 
  ;; define a function
  (+ x y)))
(add 1 1)

(define factorial 
  (lambda (n)
    (if (= n 0)
        1
        (* n (factorial (- n 1))))))
(factorial 5)

(define list '(1 2 3 4))
list 